A substrate processing process of supplying plasma-processed gas onto a heated substrate to etch a surface of the substrate is performed as one process of manufacturing semiconductor devices such as DRAMs. In such a process, the substrate is mounted on the substrate supporting table whose temperature may be elevated and heated to a certain temperature, and then the plasma-processed gas is applied onto the heated substrate.
When performing plasma processing, it is preferable to maintain the temperature of the substrate to a constant. However, when the substrate is exposed to plasma, the substrate is heated by radiant heat from the plasma as well as heat conduction from the substrate supporting table. Therefore, in the above-described substrate processing process, the heating operation by the substrate supporting table is stopped after the start of applying the plasma onto the substrate.
However, when desiring to regulate the temperature of the substrate during the plasma processing, for example, at a temperature lower than or equal to 90 degrees Celsius, it is sometimes difficult to prevent the temperature of the substrate from rising by stopping the heating operation of the substrate supporting table.